Boeing Co. said Friday it believes Canada will follow through on its threat and abandon plans to buy 18 F/A-18 Super Hornet aircraft in a $5.2 billion deal, in the latest fallout from heightened trade tensions between Ottawa and Washington.

Canadian Prime Minister Justin Trudeau warned in recent months it was prepared to cease doing business with Boeing, after the Chicago-based company filed a trade complaint with the U.S. Commerce Department alleging Montreal-based Bombardier Inc. unfairly benefited from state subsidies....